Hello,
In the context of a research project I need to add some extensions to the ClientHello during TLS handshake but I don't understand well some concepts of the custom extensions.
I can successfully send custom extensions between my client and server thanks to the SSL_CTX_add_custom_ext function but I have a hard time to use these values.
I currently define them like this on both sides: SSL_CTX_add_custom_ext(ssl_ctx, 101, SSL_EXT_CLIENT_HELLO, addScalar, freeScalar, NULL, parseScalar, NULL);
What I want to do is to store the value of the extension in a structure linked with with each SSL sessions pointer I have but the callbacks are set at the context level so I don't think I can give pointers to my structures easily as they do no exist yet when the custom extension is defined.
I think it may be possible to keep a global map with SSL session pointers as keys but I am not sure it is the way to do.
Or maybe I can do a 1:1 with only a session per context but it looks suboptimal.
In the same way, is it possible for a SSL client to set a specific value for a custom extension if it only has access to a SSL pointer? (in my case it would be better if I have only one SSL_CTX for all SSL clients)
Is what I'm trying to do feasible?
Regards,
Xavier Marchal
